Method for tightening fixing band and constant velocity universal joint apparatus

ABSTRACT

A fixing band-tightening apparatus comprises a holding section for gripping a shaft section at both ends in an axial direction, the holding section being provided rotatably in a circumferential direction in accordance with a driving action of a rotary driving source, a stopper section arranged in a lateral direction substantially horizontal with respect to the holding section, for positioning a projection of a fixing band in the lateral direction except for a vertical direction, and a band-tightening section for forcibly nipping the projection of the fixing band positioned by the stopper section to tighten the fixing band.

This application is a divisional of co-pending application Ser. No.09/677,031, filed on Sep. 29, 2000, the entire contents of which arehereby incorporated by reference and for which priority is claimed under35 U.S.C. §120; and this application claims priority of application Ser.Nos. 11-279848, 2000-157195 and 2000-217936 filed in Japan on Sep. 30,1999, May 26, 2000 and July 18, 2000, respectively under 35 U.S.C. §119.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and a method fortightening a fixing band, which make it possible to tighten the fixingband to be used, for example, to fix a boot installed to a constantvelocity universal joint. The present invention also relates to aconstant velocity universal joint apparatus.

2. Description of the Related Art

A constant velocity universal joint has been hitherto used for a drivingforce-transmitting section of a vehicle such as an automobile in orderto transmit the rotary force of a driving shaft to respective axles viaa driven shaft. A bellows-shaped boot is installed to the constantvelocity universal joint. The boot functions to ensure the liquid-tightperformance for lubricating oil enclosed in an outer cup and prevent theinside of the outer cup from invasion of dust, water, and the like.

The boot comprises a bellows section which has a bellows-shapedconfiguration, a large diameter annular attachment section which isinstalled to an outer circumferential surface of the outer cup, and asmall diameter annular attachment section which is installed to an outercircumferential surface of a shaft on the driven side, wherein the largediameter annular attachment section and the small diameter annularattachment section are formed integrally at both ends of the bellowssection. Fixing bands for the large diameter and for the small diameterare constricted to the large diameter annular attachment section and thesmall diameter annular attachment section respectively.

Usually, such a boot is formed of a rubber material. However, it isdifficult to respond to the recent demand, for example, for the highspeed durability and the durability against temperature. Therefore, aboot, which is based on the use of a synthetic resin material in placeof the rubber material, is often adopted. The boot made of resin hasrigidity, and it scarcely suffers from warpage or the like as well, ascompared with the boot made of rubber.

A technical concept is disclosed in Japanese Laid-Open PatentPublication No. 7-251336, in which the fixing band is automaticallyinstalled by mechanically tightening the fixing band. A band-fixingapparatus, which is disclosed in Japanese Laid-Open Patent PublicationNo. 7-251336, is provided with a positioning mechanism for the axialdirection and a temporary positioning mechanism for the circumferentialdirection. A method is adopted, in which a projection of the fixingband, which is temporarily positioned at an upper portion of the boot bythe temporary positioning mechanism for the circumferential direction,is forcibly nipped and deformed by a pawl mechanism to reduce thediameter of the fixing band so that the boot is fixed to a drive shaft.

That is, the band-fixing apparatus, which is disclosed in JapaneseLaid-Open Patent Publication No. 7-251336, is operated such that theprojection of the fixing band is sensed by a photoelectric sensor tostop the driving of a motor on the basis of an output of thephotoelectric sensor. Accordingly, the position is temporarilydetermined in the circumferential direction so that the projection ofthe fixing band is disposed at the upper portion of the boot, and theprojection is forcibly nipped and deformed by the aid of the pawlmechanism.

However, in the case of the band-fixing apparatus concerning theconventional technique described above, the projection of the fixingband is forcibly nipped in the state of being temporarily positioned atthe upper portion of the boot. Therefore, a problem arises such that itis impossible to make application to an existing tightening apparatusfor a fixing band which has been hitherto used by the present applicant.

That is, the present applicant has proposed a method for fixing a bootin which the boot made of rubber is wound with a steel belt, and anoverlapped portion of the steel belt is irradiated with a laser beam sothat the overlapped portion is welded and fused (see Japanese PatentPublication No. 58-34710). When the method for fixing the boot proposedby the present applicant is applied to a boot made of rubber for atripod type constant velocity universal joint on the inboard side asshown in FIG. 27, while a boot made of resin is used for a bar fieldtype constant velocity universal joint on the outboard side, then it isdemanded that the tightening position for the fixing band for fixing theboot made of resin resides in an identical positional relationship withrespect to the position for the welding and fusion effected by radiatingthe laser beam.

In other words, the laser beam apparatus for welding and fusing thesteel belt to the boot made of rubber is arranged in the substantiallyhorizontal direction (lateral direction) with respect to the constantvelocity universal joint on the inboard side. Therefore, in view of thelayout at the installation place, if the technical concept disclosed inJapanese Laid-Open Patent Publication No. 7-251336 is applied, aninconvenience arises such that the equipment investment is excessive,and the production cost is expensive.

If the technical concept disclosed in Japanese Laid-Open PatentPublication No. 7-251336 is applied, it is necessary to change theexisting production line. Also in this viewpoint, the excessiveequipment investment is required.

When the boot made of resin is fixed by tightening the fixing band froma position disposed in the substantially horizontal direction (lateraldirection) with respect to the constant velocity universal joint on theoutboard side, it is demanded that the projection of the fixing band ispositioned at a position other than the upper and lower portions of theboot, for example, at a position disposed in the substantiallyhorizontal direction (lateral direction) to tighten the fixing band.

The boot made of resin is produced by means of the blow molding or theinjection molding. A plurality of boots made of resin are accommodatedand transported in a bucket after the production. For example, a hollowportion of a boot made of resin, which is stacked on the lower sideduring the transport, is crushed, and a bellows section of the boot madeof resin is deformed in some cases, probably because of the followingreason. That is, no sufficient cooling time is consumed during themolding process for the resin for the boot made of resin. Therefore,when the plurality of boots made of resin are stacked, then any load isapplied to the bellows section, and the bellows section is deformed.

If the fixing band is installed to the boot made of resin deformed asdescribed above by using the band-fixing apparatus concerning theconventional technique described above, the following inconveniencearises as shown in FIG. 43. That is, when the projection of the fixingband is forcibly nipped, the pawl mechanism makes approach to contactwith the deformed portion of the bellows section of the boot made ofresin. As a result, the bellows section is damaged. When the pawlmechanism contacts with the bellows section, the back and forth movementof the pawl mechanism is obstructed. It is feared that any troubleoccurs, for example, such that the operation of the band-fixingapparatus is stopped.

When the large diameter annular attachment section of the boot made ofresin is installed to the outer circumferential surface of an outer cuptogether with the loosely fitted fixing band having a large diameter,and the fixing band having the large diameter is tightened, if the largediameter annular attachment section of the boot made of resin isinstalled in a state of being deviated from a normal position withrespect to the outer circumferential surface of the outer cup, then thefollowing inconvenience arises. That is, the large diameter annularattachment section is fixed by the fixing band in a state in which it issubjected to any positional discrepancy. Similarly, anotherinconvenience also arises such that the small diameter annularattachment section is fixed by the fixing band in a state in which it issubjected to any positional discrepancy.

The technical concept, in which the projection is provided at a portionat which the fixing band for the boot for the constant velocityuniversal joint is installed, is disclosed, for example, in JapaneseLaid-Open Utility Model Publication No. 1-75629, Japanese Utility ModelPublication No. 63-11429, Japanese Utility Model Publication No.62-16541, and Japanese Utility Model No. 2598540.

In the technical concept disclosed in Japanese Laid-Open Utility ModelPublication No. 1-75629, a projection is provided in order to avoid theoccurrence of crack at a portion at which a band is installed. In thetechnical concept disclosed in Japanese Utility Model Publication No.63-11429, a projection is provided in order to improve the installationperformance by giving the flexibility to a boot made of hard resin. Inthe technical concept disclosed in Japanese Utility Model PublicationNo. 62-16541, a projection tab is provided in order to improve thestrength and the sealing performance. In the technical concept disclosedin Japanese Utility Model No. 2598540, a small projecting strip isprovided in order to facilitate the assembling performance by decreasingthe rigidity of the fixed end.

As described above, the technical concepts disclosed in these patentdocuments are completely different from the invention of thisapplication in problem to be solved. Objects, constructions, functions,and effects of them are conspicuously different from those of theinvention of this application.

That is, in the technical concepts disclosed in the precedingtechniques, the projection is provided in order to improve thetightening force of the fixing band, or the projection is provided, forexample, for the purpose of improving the installation performance,improving the sealing performance, or facilitating the assemblingperformance. On the other hand, the invention of this application isdifferent from the above in the following points. That is, when a fixingband is constricted by using a fixing band-tightening apparatus, thefrictional coefficient between a boot made of resin and the fixing bandis increased in order to avoid the loose rotation of the fixing bandwith respect to the boot made of resin. The projection of the fixingband, which may be rotated integrally with the boot made of resin, isforcibly nipped, for example, in a state of being positioned at aposition disposed in a substantially horizontal direction. By doing so,the fixing band is tightened and constricted.

In other words, it is enough that a frictional coefficient-increasingmechanism, which is one of the features of the invention of thisapplication, persistently exhibits the function sufficient to integrallyrotate the fixing band when the fixing band is constricted by using thefixing band-tightening apparatus. The frictional coefficient-increasingmechanism does not function to increase the tightening force for thefixing band. In this viewpoint, the invention of this application isclearly different from the technical concepts disclosed in the precedingtechniques.

SUMMARY OF THE INVENTION

A general object of the present invention is to provide a constantvelocity universal joint apparatus and an apparatus and a method fortightening a fixing band, which make it possible to harmonize the layoutwith an existing fixing band-tightening apparatus by tightening aprojection of the fixing band in a state of being positioned at aposition except for an upper portion and a lower portion of a boot sothat the versatility is improved.

A principal object of the present invention is to provide a fixingband-tightening apparatus which makes it possible to smoothly install afixing band without making contact with a bellows section even when aboot made of resin is deformed.

Another object of the present invention is to provide a fixingband-tightening apparatus which makes it possible to reliably installlarge diameter and small diameter annular attachment sections of a bootmade of resin to predetermined positions subjected to positioning.

Still another object of the present invention is to provide a fixingband-tightening method for a boot for a constant velocity universaljoint, which is preferably used for the fixing band-tightening apparatusdescribed above and which makes it possible to integrally rotate afixing band and the boot made of resin in a reliable manner byincreasing the coefficient of friction when the fixing band is tightenedand fixed by using the fixing band-tightening apparatus.

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings in which a preferredembodiment of the present invention is shown by way of illustrativeexample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view illustrating a fixing band-tighteningapparatus according to an embodiment of the present invention;

FIG. 2 shows a plan view illustrating the fixing band-tighteningapparatus;

FIG. 3 shows a perspective view illustrating a holding section forconstructing the fixing band-tightening apparatus;

FIG. 4 shows a longitudinal sectional view illustrating a first holdingmechanism for constructing the holding section;

FIG. 5 shows a longitudinal sectional view illustrating a second holdingmechanism for constructing the holding section;

FIG. 6 shows a plan view illustrating a bellows section-pressingmechanism for constructing the holding section;

FIG. 7 shows, with partial cutout, a front view illustrating a largediameter side end-positioning mechanism for constructing the holdingsection;

FIG. 8 shows, with partial omission, a vertical sectional viewillustrating a state in which a collar for constructing the largediameter side end-positioning mechanism abuts against a large diameterannular attachment section of a boot made of resin, and the collar ispositioned;

FIG. 9 shows a view as viewed in a direction of an arrow T shown in FIG.3, illustrating a small diameter side end-positioning mechanism;

FIG. 10 shows a vertical sectional view taken along a line X—X shown inFIG. 9;

FIG. 11 shows a perspective view illustrating a first stopper mechanismfor constructing a stopper section;

FIG. 12 shows a perspective view illustrating a second stopper mechanismfor constructing the stopper section;

FIG. 13 shows a perspective view illustrating a first tighteningmechanism for constructing a band-tightening section;

FIG. 14 shows a perspective view illustrating a second tighteningmechanism for constructing the band-tightening section;

FIG. 15 shows a partial longitudinal sectional view taken along an axialdirection of the first tightening mechanism;

FIG. 16 shows a cross-sectional view taken along the axial direction ofthe first tightening mechanism;

FIG. 17 illustrates an operation effected when the stopper section andthe band-tightening section are at initial positions;

FIG. 18 illustrates an operation depicting a state in which a stopperplate for constructing the stopper section abuts against a projection ofa fixing band and it is positioned;

FIG. 19 illustrates an operation depicting a state in which theprojection of the fixing band is detected by using a sensor contained ina first end of a stopper block;

FIG. 20 illustrates an operation depicting a state in which the stopperblock is moved downwardly to make abutment against the projection afterdetecting the projection of the fixing band by using the sensor;

FIG. 21 shows, with partial cross section, a side view in a state inwhich the first end of the stopper block abuts against the projection;

FIG. 22 shows, with partial cutout, a front view in a state in which thefirst end of the stopper block abuts against the projection;

FIG. 23 shows an operation illustrating a state in which theband-tightening section is displaced, and the projection of the fixingband is held by the holding section;

FIG. 24 shows a partial magnified longitudinal sectional viewillustrating a state in which the projection of the fixing band ispositioned by the stopper block, and it is held by the holding section;

FIG. 25 shows a partial magnified longitudinal sectional viewillustrating a state in which a shaft is displaced starting from thestate shown in FIG. 21, and the projection of the fixing band isforcibly nipped by pawls;

FIG. 26 shows an operation illustrating a state in which the projectionof the fixing band is forcibly nipped by the pawls;

FIG. 27 shows a longitudinal sectional view taken along an axialdirection of a drive shaft to which a bar field type constant velocityuniversal joint is connected at one end and a tripod type constantvelocity universal joint is connected at the other end;

FIG. 28 shows a view as viewed in a direction of an arrow G shown inFIG. 21, illustrating the fixing band;

FIG. 29 shows, with partial omission, a longitudinal sectional viewillustrating an arrangement of a constant velocity universal joint in astate in which the fixing band is loosely fitted to the boot made ofresin by applying a fixing band-tightening method for the boot made ofresin for the constant velocity universal joint;

FIG. 30 shows, with partial omission, a perspective view illustratingthe boot made of resin shown in FIG. 29;

FIG. 31 shows a partial magnified vertical sectional view illustrating alarge diameter annular attachment section for constructing the boot madeof resin shown in FIG. 29;

FIG. 32 shows a magnified vertical sectional view taken along a lineXXXII—XXXII shown in FIG. 31;

FIG. 33 shows a partial magnified vertical sectional view in whichapexes of first and second small projections shown in FIG. 31 are formedto have an acute-angled configuration;

FIG. 34 shows a vertical sectional view illustrating the large diameterannular attachment section as viewed in a direction substantiallyperpendicular to an axis of a driven shaft;

FIG. 35 shows a partial magnified vertical sectional view illustrating asmall diameter annular attachment section for constructing the boot madeof resin shown in FIG. 29;

FIG. 36 shows a magnified vertical sectional view taken along a lineXXXVI—XXXVI shown in FIG. 35;

FIG. 37 shows a vertical sectional view illustrating the small diameterannular attachment section as viewed in a direction substantiallyperpendicular to the axis of the driven shaft;

FIG. 38 shows, with partial omission, a perspective view illustrating afirst modified embodiment of a small projection formed in aband-mounting groove;

FIG. 39 shows, with partial omission, a plan view illustrating a bootmade of resin shown in FIG. 38;

FIG. 40 shows, with partial omission, a vertical sectional viewillustrating the boot made of resin shown in FIG. 38;

FIG. 41 shows, with partial omission, a vertical sectional viewillustrating a state in which a small projection is formed on a sideopposite to one shown in FIG. 40;

FIG. 42 shows, with partial omission, a vertical sectional viewillustrating a second modified embodiment of a small projection formedin a band-mounting groove; and

FIG. 43 shows a partial sectional front view illustrating a deformedstate of a bellows section of a boot made of resin, which arises when aband-fixing apparatus concerning a conventional technique is used.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A fixing band-tightening apparatus 10 according to an embodiment of thepresent invention is shown in FIGS. 1 and 2.

A drive shaft 16 is used as a workpiece, to which a bar field typeconstant velocity universal joint 12 is connected to one end, and atripod type constant velocity universal joint 14 is connected to theother end. A boot 18 made of resin is installed to the bar field typeconstant velocity universal joint 12, and a boot 20 made of rubber isinstalled to the tripod type constant velocity universal joint 14 (seeFIG. 27).

The fixing band-tightening apparatus 10 is arranged on a base 22 havinga substantially T-shaped configuration. The fixing band-tighteningapparatus 10 comprises a holding section 26 for rotatably holding theworkpiece in accordance with the driving action of a rotary drivingsource 24; a stopper section 32 arranged in a lateral directionsubstantially horizontal with respect to the holding section 26, forpositioning a projection 30 of each of fixing bands 28 a, 28 b in asubstantially horizontal state; and a band-tightening section 34 forforcibly nipping the projection 30 of each of the fixing bands 28 a, 28b positioned by the stopper section 32 to tighten the fixing bands 28 a,28 b.

As shown in FIG. 3, the holding section 26 comprises a first holdingmechanism 38 fixed on first plates 36 a, 36 b, for holding a shaftsection of the bar field type constant velocity universal joint 12; asecond holding mechanism 42 separated by a predetermined distance fromthe first holding mechanism 38, for holding a shaft section of thetripod type constant velocity universal joint 14; a bellowssection-pressing mechanism 37 (see FIG. 6) provided on the side of thefirst holding mechanism 38, for pressing a deformed portion of a bellowssection 35 of the boot 18 made of resin; and an end-positioningmechanism 39 provided on the side of the first holding mechanism 38, forpositioning each of a large diameter annular attachment section and asmall diameter annular attachment section of the boot 18 made of resinat a predetermined position.

The end-positioning mechanism 39 comprises a large diameter sideend-positioning mechanism 39 a for positioning the large diameterannular attachment section of the boot 18 made of resin at thepredetermined position on the outer circumferential surface of a cupsection 83, and a small diameter side end-positioning mechanism 39 b forpositioning the small diameter annular attachment section of the boot 18made of resin at the predetermined position on the outer circumferentialsurface of the drive shaft 16.

As shown in FIG. 4, the first holding mechanism 38 is provideddisplaceably integrally with the first plate 36 a in the direction ofthe arrow A or B by the aid of a linear guide 43 in accordance with thedriving action of a cylinder 41. As shown in FIG. 5, the second holdingmechanism 42 is provided displaceably in the direction of the arrow A orB by the aid of a linear guide 45 installed on the second plate 40.

The first holding mechanism 38 and the second holding mechanism 42 arearranged coaxially and mutually opposingly, and they are constructed insubstantially the same manner except for the bellows section-pressingmechanism 37 and the end-positioning mechanism 39. Therefore, detailedexplanation will be made for only the first holding mechanism 38.Constitutive components of the second holding mechanism 42 correspondingto those of the first holding mechanism 38 are designated by the samereference numerals, detailed explanation of which will be omitted.

As shown in FIG. 4, the first holding mechanism 38 has a chuck mechanism48 which is connected to the drive shaft of the rotary driving source 24via a coupling member 46. The coupling member 46 and the chuck mechanism48 are rotatably supported in a first holder 52 and in a second holder54 respectively by the aid of a plurality of bearing members 50 a to 50d. The first holder 52 is provided with a pressure fluid supply port 59for supplying a pressure fluid via a communication passage 56communicating with the chuck mechanism 48.

The chuck mechanism 48 includes a cylinder tube 58 which is connected tothe coupling member 46 and which is rotatably supported in the secondholder 54, a piston 62 which is provided slidably along a cylinderchamber 60 communicating with the communication passage 56, a springmember 64 which urges the piston 62 toward the direction of the arrow A,and a cup member 68 which is connected to the piston 62 via a shaft 66for making displacement integrally with the piston 62.

The chuck mechanism 48 further includes a pair of arms 72 a, 72 b whichare provided with their first ends capable of making approach orseparation with support points of a set of pins 70 a, 70 b by makingengagement with an opening of the cup member 68, and a pair of pinchingblocks 78 a, 78 b which are swingably attached via long holes 74 tofirst ends of the pair of arms 72 a, 72 b and which are formed with arecess 76 for clamping the shaft section of the outer cup forconstructing the constant velocity universal joint 12. A spring member80, which is used to urge the pair of pinching blocks 78 a, 78 b indirections to make separation from each other, is installed between thepair of pinching blocks 78 a, 78 b.

In this arrangement, the piston 62 and the cup member 68 are displacedin an integrated manner in the direction of the arrow B against theresilient force of the spring member 64 in accordance with the action ofthe pressure fluid introduced from the pressure fluid supply port 59 viathe communication passage 56 into the cylinder chamber 60. During thisprocess, the pair of arms 72 a, 72 b are engaged with the opening of thecup member 68. In accordance with the engaging action, the first ends ofthe pair of arms 72 a, 72 b are displaced in the directions to makeapproach to one another by using the support points of the pins 70 a, 70b. As a result, the pair of pinching blocks 78 a, 78 b, which areswingably attached to the first ends of the pair of arms 72 a, 72 b,make approach to one another against the resilient force of the springmember 80. Thus, the shaft section 49 of the constant velocity universaljoint 12 is held by the aid of the recess 76.

When the shaft section 49 is released from the holding state to detachthe constant velocity universal joint 12, the pressure fluid supply port59 is allowed to make communication with the atmospheric air inaccordance with the switching action of an unillustrated changeovervalve to decrease the pressure in the cylinder chamber 60. Accordingly,the piston 62 and the cup member 68 are displaced in the direction(direction of the arrow A) opposite to the above in accordance with theresilient force of the spring member 64. Therefore, the pair of arms 72a, 72 b are released from the pressurizing force having been applied bythe opening of the cup member 68. The pair of pinching blocks 78 a, 78 bare displaced in directions to make separation from each other by theaid of the resilient force of the spring member 80.

As shown in FIG. 7, the large diameter side end-positioning mechanism 39a comprises a cylinder 67 which is fixed to one side surface of thesecond holder 54, a pair of piston rods 69 a, 69 b which aredisplaceable in the substantially horizontal direction in accordancewith the driving action of the cylinder 67, a displacement member 73which is connected to first ends of the piston rods 69 a, 69 b via aplate 71, a pair of rollers 77 a, 77 b which are rotatably supported byarms 75 a, 75 b of the displacement member 73, and a substantiallycylindrical collar 81 to which an annular member 79 for being engagedwith the pair of rollers 77 a, 77 b is externally fitted.

The collar 81 is formed to have a cylindrical configuration having ahole with substantially the same diameter as the diameter of the cupsection 83 of the constant velocity universal joint 12, and it isprovided rotatably about the center of rotation of the axis of shaftsection 49 of the constant velocity universal joint 12 in accordancewith the engaging action of the annular member 79 with the pair ofrollers 77 a, 77 b.

A pair of guide rails (not shown), which are opposed to one another andwhich extend in the axial direction, are installed to the outercircumferential surface of the cylinder tube 58 for surrounding the pairof pinching blocks 78 a, 78 b. The collar 81 is provided displaceably inthe direction of the arrow A or B in accordance with the guiding actionof the unillustrated guide rails.

Therefore, the collar 81 is displaced in the direction of the arrow B inaccordance with the driving action of the cylinder 67. As shown in FIG.8, the collar 81 functions to surround the outer circumferential surfaceof the cup section 83 so that the first end 81 a of the collar 81 abutsagainst the large diameter annular attachment section of the boot 18made of resin to position the large diameter annular attachment sectionat a predetermined position on the outer circumferential surface of thecup section 83. The fixing band 28 a is tightened by rotating theconstant velocity universal joint 12 while maintaining the state inwhich the large diameter annular attachment section is positioned by thecollar 81.

As shown in FIGS. 2, 3, 6, 9, and 10, the small diameter sideend-positioning mechanism 39 b has a first cylinder 87 which is fixedlyprovided on the plate 85, a first connecting plate 91 which is connectedto a piston rod 89 of the first cylinder 87, a second cylinder 93 whichis connected to the first connecting plate 91 and which is provideddisplaceably in the substantially horizontal direction (direction of thearrow A or B) in accordance with the driving action of the firstcylinder 87, a second connecting plate 97 which is connected to a pistonrod 95 of the second cylinder 93, and a chuck member 99 which isconnected to the second connecting plate 97 and which is provideddisplaceably in the substantially vertical direction (direction of thearrow E or F) in accordance with the driving action of the secondcylinder 93.

As shown in FIG. 10, the chuck member 99 is provided with a pair ofsupport members 47 a, 47 b which make mutually approach or separation inthe directions of the arrows in accordance with the driving action ofthe chuck member 99. The pair of support members 47 a, 47 b are providedwith four support blocks 103 a to 103 d for rotatably supporting theouter circumferential surface of the drive shaft 16 by the aid ofrollers 101 a to 101 d which are rotatably attached thereto. Pin members107 abut against projections 105 of the support blocks 103 a to 103 d.The pin member 107 is provided so that a first end of a spring member109 installed in a hole is fastened thereto. The spring members 109 areprovided to absorb the shock applied to the support blocks 103 a to 103d. Reference numeral 111 indicates stoppers for fastening the supportblocks 103 a to 103 d.

The support block 103 a to 103 d is formed with a circular arc-shapedprojection 113 a to 113 d which is formed by being bent in a circulararc-shaped vertical cross section and which protrudes by a predeterminedlength in the axial direction of the drive shaft 16. A first circulararc surface 125 and a second circular arc surface 127, which havemutually different radiuses of curvature, are formed on the innercircumferential surface of the circular arc-shaped projection 113 a to113 d in order to respond to various drive shafts 16 having differentdiameters.

For example, the following arrangement is adopted. That is, when thediameter of the drive shaft 16 is maximum, the first circular arcsurfaces 125 of the support blocks 103 a to 103 d are engaged with theouter circumferential surface of the drive shaft 16 (see solid line inFIG. 10). When the diameter of the drive shaft 16 is minimum (seetwo-dot chain line in FIG. 10), then the support blocks 103 a to 103 dmake approach to one another, and the second circular arc surfaces 127of the support blocks 103 a to 103 d are engaged with the outercircumferential surface of the drive shaft 16.

Therefore, the support blocks 103 a to 103 d make bending displacementalong the arrow R shown in FIG. 9 in accordance with the driving actionof the first and second cylinders 87, 93. When the chuck member 99 isdriven to allow the pair of support members 47 a, 47 b to make approachto one another, the drive shaft 16 is rotatably supported by the rollers101 a to 101 d of the four circular arc-shaped projections 113 a to 113d. In this arrangement, the small diameter annular attachment section ofthe boot 18 made of resin is regulated by the ends of the four circulararc-shaped projections 113 a to 113 d. Accordingly, the small diameterannular attachment section is positioned at a predetermined position ofthe drive shaft 16 (see FIGS. 6 and 9).

As shown in FIGS. 2, 3, and 6, the bellows section-pressing mechanism 37has a cylinder 53 which is connected to the first support member 47 b bythe aid of an attachment member 51 and which is arranged to be inclinedby a predetermined angle with respect to the axis of the drive shaft 16as viewed in a plan view, a pressing plate 61 which is provided movablyback and force in the direction of the arrow L or M in accordance withthe driving action of the cylinder 53 by the aid of a connecting member57 installed to the first end of a piston rod 55, and a guide rod 63which has its first end connected to the connecting member 57 and whichhas its second end provided insertably with respect to a hole of theattachment member 51.

In this arrangement, the bellows section-pressing mechanism 37 isprovided to make displacement integrally with the first support member47 b in the substantially vertical direction and in the substantiallyhorizontal direction in accordance with the driving action of the firstand second cylinders 87, 93.

The pressing plate 61 is formed in a bent manner to have a substantiallyL-shaped cross section. A flat surface section 65, which abuts againstthe bellows section 35 on the side of the small diameter annularattachment section of the boot 18 made of resin, is formed to have asubstantially U-shaped configuration having a hole (not shown) largerthan the small diameter annular attachment section (see FIG. 3). Thehole of the flat surface section 65 is not limited to the substantiallyU-shaped configuration. For example, the hole may be formed to have asubstantially V-shaped configuration.

The stopper section 32 comprises a first stopper mechanism 82 (see FIG.11) for positioning the projection 30 of the fixing band 28 b to beinstalled to the small diameter annular attachment section of the boot18 made of resin, and a second stopper mechanism 84 (see FIG. 12) forpositioning the projection 30 of the fixing band 28 a to be installed tothe large diameter annular attachment section of the boot 18 made ofresin.

As shown in FIG. 11, the first stopper mechanism 82 comprises a thirdplate 86 which is fixedly provided on the base 22, a first cylinder 90which is fixed on the third plate 86 by the aid of a pair of fixtures 88a, 88 b, and a fourth plate 98 which is connected to a first end of apiston rod 94 of the first cylinder 90 via an L-shaped block 92 andwhich is provided displaceably linearly in accordance with the guidingaction of a linear guide 96. The linear guide 96 comprises a lengthyguide rail 100, and a guide block 102 which makes sliding displacementalong the guide rail 100.

The first stopper mechanism 82 has a fifth plate 104 which is connectedsubstantially perpendicularly to a first end of the fourth plate 98, asecond cylinder 106 which is fixedly provided on a side surface portionof the fifth plate 104, a pair of substantially parallel shafts 112which are connected to a first end of a piston rod 108 of the secondcylinder 106 via a connecting member 110, a block member 114 which isfixed to the fifth plate 104 and which guides the pair of shafts 112 bythe aid of unillustrated guide holes for inserting the pair of shafts112 therethrough, and a substantially L-shaped bent member 116 which isconnected to first ends of the pair of shafts 112 by the aid of screwmembers.

The bent member 116 is provided with a stopper block 118 which hangssubstantially in the vertical direction. A first end 118 a of thestopper block 118 functions to make abutment against the projection 30of the fixing band 28 b so that the projection 30 is positioned in asubstantially horizontal state as described later on.

One or a plurality of tubes 119 a, 119 b, which are connected to anunillustrated air supply source, are retained by the bent member 116.When the boot 18 made of resin and the fixing band 28 b are rotated inan integrated manner in accordance with the driving action of the rotarydriving source 24, the fixing band 28 b installed to the small diameterannular attachment section of the boot 18 made of resin may be rotatedin unison with the boot 18 made of resin. When the air is dischargedfrom blow ports 120 of the tubes 119 a, 119 b toward the rotating fixingband 28 b, the fixing band 28 b to be installed to the small diameterannular attachment section can be prevented from the co-rotation.

In this arrangement, the stopper block 118 and the tubes 119 a, 119 bare provided displaceably in the substantially horizontal direction(direction of the arrow C or D) in accordance with the driving action ofthe first cylinder 90, and they are provided displaceably in thevertical direction (direction of the arrow E or F) in accordance withthe driving action of the second cylinder 106.

A sixth plate 115, which extends in a substantially horizontaldirection, is fixed to the block member 114. A first sensor 117 fordetecting the timing of the downward movement of the stopper block 118is installed to the sixth plate 115 in a state of being inclined by apredetermined angle (see FIG. 11). The first sensor 117 is provided todetect the projection of the fixing band 28 b in the rotating statebefore arrival at the substantially horizontal state so that the firststopper mechanism 82 is energized on the basis of a detection signaloutputted from the first sensor 117 to move the stopper block 118downwardly.

A second sensor 121 for detecting the projection 30 is contained in afirst end 118 a of the stopper block 118 which makes abutment againstthe projection 30 of the fixing band 28 b (see FIG. 21). The secondsensor 121 is arranged at a position deviated by a predetermineddistance in a substantially horizontal direction from a substantiallycentral portion of the first end of the stopper block 118 (see FIG. 22).

Each of the first sensor 117 and the second sensor 121 is composed of,for example, a distance-setting type photoelectric switch to receive areflected light beam reflected after hitting the workpiece. Accordingly,the spacing distance between the workpiece and each of the first sensor117 and the second sensor 121 is detected. The output signal is derivedwhen the spacing distance detected by each of the first sensor 117 andthe second sensor 121 is coincident with a preset distance.

The second stopper mechanism 84 is constructed in substantially the samemanner as the first stopper mechanism 82. As shown in FIG. 12, theformer is different from the latter in that the stopper block 118 isprovided with a pressing tab 123 for making contact under pressure withthe projection 30 by the aid of the resilient force of a spring member122. When the boot 18 made of resin and the fixing band 28 a are rotatedin an integrated manner in accordance with the driving action of therotary driving source 24, the fixing band 28 a, which is installed tothe large diameter annular attachment section of the boot 18 made ofresin, may be rotated together with the boot 18 made of resin to give awavy state. When the pressing tab 123 makes contact under pressure withthe fixing band 28 a in accordance with the action of the resilientforce of the spring member 122, it is possible to avoid the wavy stateof the fixing band 28 a installed to the large diameter annularattachment section.

The band-tightening section 34 comprises a first tightening mechanism124 (see FIG. 13) for forcibly nipping the projection 30 of the fixingband 28 b to be installed to the small diameter annular attachmentsection of the boot 18 made of resin, and a second tightening mechanism126 (see FIG. 14) for forcibly nipping the projection 30 of the fixingband 28 a to be installed to the large diameter annular attachmentsection of the boot 18 made of resin. In this arrangement, the firsttightening mechanism 124 and the second tightening mechanism 126 areconstructed in substantially the same manner. The first tighteningmechanism 124 will be explained in detail below. Constitutive componentsof the second tightening mechanism 126 corresponding to those of thefirst tightening mechanism 124 are designated by the same referencenumerals, explanation of which will be omitted.

As shown in FIG. 13, the first tightening mechanism 124 includes aseventh plate 128 which is fixedly provided on the base 22, a thirdcylinder 132 which is fixed to the seventh plate 128 by the aid offixing fixtures 130 a, 130 b, and a lengthy eighth plate 138 which isconnected to a first end of a piston rod 134 of the third cylinder 132and which is provided displaceably linearly in accordance with theguiding action of a linear guide 136. The linear guide 136 comprises alengthy guide rail 140 and a pair of guide blocks 142 which are providedslidably along the guide rail 140.

The first tightening mechanism 124 further includes a fourth cylinder146 which is fixedly provided on an upper surface portion of the eighthplate 138 by the aid of a pair of fixing fixtures 144 a, 144 b, a jointmeans 152 which is connected to a first end of a piston rod 148 of thefourth cylinder 146 and which is provided with a shaft 150 fortransmitting the forward/backward movement of the piston rod 148thereto, and a forcible nipping means 153 which is fixed to the eighthplate 138 and which is provided with a hole for inserting a first end ofthe shaft 150 therethrough.

The joint means 152 has a guide block 156 and a ninth plate 158 whichare provided slidably along a guide rail 154 fixed to the eighth plate138, a plurality of connecting members 160 which are fixed on the ninthplate 158, the shaft 150 to which the forward/backward movement of thepiston rod 148 is transmitted via the plurality of connecting members160, and a block 162 which prevents the shaft 150 from rotation andwhich supports the shaft 150. The shaft 150 is provided at its first endwith an engaging section 166 which is formed to be gradually thin-walledby mutually opposing inclined surfaces 164 a, 164 b as viewed from alateral position (see FIG. 15) and which is formed to have a rectangularsubstantially flat plate-shaped configuration as viewed from an upperposition (see FIG. 16).

The forcible nipping means 153 includes a housing 170 which is fixed tothe eighth plate 138 and which has a through-hole 168 formed at theinside to make sliding movement of the shaft 150, and a pair of forciblenipping segments 174 a, 174 b which are provided in the verticaldirection at an opening of the housing 170 and which are provided attheir first ends with sharp pawls 172 a, 172 b for forcibly nipping theprojection 30. As shown in FIGS. 24 and 25, the pair of forcible nippingsegments 174 a, 174 b are provided with the pawls 172 a, 172 b which arecapable of making approach or separation with the support points of pins176 rotatably attached at substantially central portions respectively.Rollers 178 are rotatably attached to second ends of the forciblenipping segments 174 a, 174 b. An engaging section 166, which is formedat a first end of the shaft 150, is engaged between the pair of rollers178. When the shaft 150 is displaced in the direction of the arrow D,and the engaging section 166 is wedged into the space between the pairof rollers 178, then the pair of rollers 178 are separated from eachother, and the pawls 172 a, 172 b make approach to one another with thesupport points of the pins 176. As a result, the projection 30 of thefixing band 28 b is forcibly nipped by the pawls 172 a, 172 b of thepair of forcible nipping segments 174 a, 174 b. Accordingly, the fixingband 28 b is tightened.

As shown in FIG. 16, the forcible nipping means 153 has a pressingmember 184 which is supported by a support member 180 installed to thehousing 170 and which is always urged in the direction of the arrow D bymeans of the resilient force of a spring member 182. The pressing member184 has a holding section 186 which extends in a substantiallyhorizontal direction between the pair of pawls 172 a, 172 b separatedfrom each other by a predetermined distance and which abuts against theprojection 30 of the fixing band 28 b in accordance with the action ofthe resilient force of the spring member 182 to press the projection 30.A plate 190, which is used to guide the pressing member 184 with atapered section 188 to make engagement with the bellows section of theboot 18 made of resin to protect the boot 18 made of resin, is installedto a stepped section of the housing 170.

As shown in FIGS. 13 and 14, pins 194, which protrude toward the outsidefrom the housing 170 via long holes 192, are secured to side portions ofthe pair of forcible nipping segments 174 a, 174 b respectively. Thepair of rollers 178 are always urged to make abutment by the aid of theresilient force of a spring member 196 fastened between the pair of pins194.

The fixing band-tightening apparatus 10 according to the embodiment ofthe present invention is basically constructed as described above. Next,its operation, function, and effect will be explained.

The bar field type constant velocity universal joint 12, which isconnected to the first end of the drive shaft 16, is held by the firstholding mechanism 38. The tripod type constant velocity universal joint14, which is connected to the second end of the drive shaft 16, is heldby the second holding mechanism 42. In this case, the boot 18 made ofresin is installed to the bar field type constant velocity universaljoint 12. The boot 20 made of rubber is installed to the tripod typeconstant velocity universal joint 14.

It is assumed that steel belts 198 a, 198 b have been already installedby an unillustrated apparatus to the large diameter annular attachmentsection and the small diameter annular attachment section of the boot 20made of rubber in the previous step respectively (see FIG. 27).

The fixing bands 28 a, 28 b, which are installed to the large diameterannular attachment section and the small diameter annular attachmentsection of the boot 18 made of resin respectively, are rounded in asubstantially circular configuration. The projection 30, which protrudesoutwardly, is formed at a part of each of the circumscribing fixingbands 28 a, 28 b. The first end on the outer circumferential side ofeach of the fixing bands 28 a, 28 b is fastened by inserting a pluralityof hook-shaped fastening pawls 200 a to 200 c into fastening holes 202 ato 202 c (see FIGS. 21 and 22).

At first, explanation will be made for a process in which the deformedportion of the bellows section 35 of the boot 18 made of resin ispressed by the bellows section-pressing mechanism 37, so that thedeformed portion is prevented from the contact with the pawls 172 a, 172b for forcibly nipping the projection 30 of the fixing band 28 b.

After the shaft section 49 of the constant velocity universal joint 12is gripped by the pair of pinching blocks 78 a, 78 b for constructingthe chuck mechanism 48, the cylinder 53 is driven to displace thepressing plate 61. The pressing plate 61 is displaced in the directionof the arrow L in accordance with the guiding action of the guide rod63, and the flat surface section 65, which is formed to have thesubstantially U-shaped configuration, enters the boundary portionbetween the small diameter annular attachment section and the bellowssection 35 (see FIG. 8).

Therefore, the deformed portion of the bellows section 35, which hasprotruded toward the small diameter annular attachment section, ispressed by the pressing plate 61 toward the large diameter annularattachment section. As a result, even when the bellows section 35 of theboot 18 made of resin is deformed, the fixing band 28 b can be installedto the small diameter annular attachment section without causing thecontact of the pawls 172 a, 172 b with the deformed portion of thebellows section 35.

When the cylinder 53 is further driven after the fixing band 28 b isinstalled, then the pressing plate 61 is separated from the bellowssection 35, and the initial position is restored to give the waitingstate.

Next, explanation will be made for a process in which the large diameterannular attachment section is positioned at the predetermined positionof the cup section 83 of the constant velocity universal joint 12 byusing the large diameter side end-positioning mechanism 39 a.

After the shaft section 49 of the constant velocity universal joint 12is gripped by the pair of pinching blocks 78 a, 78 b for constructingthe chuck mechanism 48, the pair of piston rods 69 a, 69 b are displacedin the direction of the arrow B by driving the cylinder 67. The collar81, which is connected to the displacement member 73, is displaced inthe direction of the arrow B in accordance with the guiding action ofthe unillustrated guide rail, in accordance with the displacement actionof the pair of piston rods 69 a, 69 b. The collar 81 enters along theouter circumferential surface of the cup section 83 of the constantvelocity universal joint 12. The first end 81 a of the collar 81 abutsagainst the end of the large diameter annular attachment section of theboot 18 made of resin (see FIG. 8).

Explanation will be made for a process in which the small diameterannular attachment section is positioned at the predetermined positionof the drive shaft 16 by using the small diameter side end-positioningmechanism 39 b in the same manner as described above.

The support blocks 103 a to 103 d are displaced along the arrow R shownin FIG. 9 in accordance with the driving action of the first and secondcylinders 87, 93, and the chuck member 99 is energized to displace thepair of support members 47 a, 47 b in the directions to make approach toone another. Accordingly, the drive shaft 16 is held by the circulararc-shaped projections 113 a to 113 d. In this process, the ends of thecircular arc-shaped projections 113 a to 113 d abut against the smalldiameter annular attachment section of the boot 18 made of resin. Thus,the small diameter annular attachment section is positioned at thepredetermined position of the drive shaft 16.

Therefore, even when the large diameter annular attachment section andthe small diameter annular attachment section of the boot 18 made ofresin are deviated from the predetermined positions, then the first end81 a of the collar 81 abuts against the large diameter annularattachment section to avoid the positional discrepancy from thepredetermined position, and the ends of the circular arc-shapedprojections 113 a to 113 d of the support blocks 103 a to 103 d abutagainst the small diameter annular attachment section to avoid thepositional discrepancy from the predetermined position. Thus, the largediameter and small diameter annular attachment sections are reliablypositioned at the predetermined positions respectively.

As described later on, when the constant velocity universal joint 12 isrotated integrally with the drive shaft 16 in accordance with thedriving action of the rotary driving source 24, the collar 81 is rotatedintegrally with the cup section 83 by the aid of the annular member 79to make engagement with the pair of rollers 77 a, 77 b. Accordingly, thefixing band 28 a can be installed to the large diameter annularattachment section while maintaining the state in which the largediameter annular attachment section is positioned at the predeterminedposition.

Similarly, the rollers 101 a to 101 d of the support blocks 103 a to 103d are rotated, and thus the fixing band 28 b can be installed to thesmall diameter annular attachment section while maintaining the state inwhich the small diameter annular attachment section is positioned at thepredetermined position.

In this case, it is preferable that the cylinders 53, 67 are operatedsubstantially simultaneously to operate the bellows section-pressingmechanism 37 and the end-positioning mechanism 39 substantiallysimultaneously.

Subsequently, explanation will be made for a process in which the fixingband 28 a having the large diameter and the fixing band 28 b having thesmall diameter, which are loosely fitted to the large diameter annularattachment section and the small diameter annular attachment section ofthe boot 18 made of resin respectively, are tightened substantiallysimultaneously.

At first, the rotary driving source 24 is driven, and thus the bar fieldtype constant velocity universal joint 12, the tripod type constantvelocity universal joint 14, and the drive shaft 16, which are coaxiallyheld by the first holding mechanism 38 and the second holding mechanism42, are rotated in an integrated manner respectively. In this process,the pair of fixing bands 28 a, 28 b are loosely fitted to the largediameter annular attachment section and the small diameter annularattachment section of the boot 18 made of resin with slight clearancesrespectively. When the boot 18 made of resin is rotated, the pair offixing bands 28 a, 28 b are also rotated in accordance therewith.Therefore, the projections 30 of the fixing bands 28 a, 28 b are in therotating state about the center of the central axis of the drive shaft16.

Subsequently, the projections 30 of the fixing bands 28 a, 28 b in therotating state before arrival at the substantially horizontal state aredetected by the first sensor 117 (see FIG. 19). The first stoppermechanism 82 and the second stopper mechanism 84, which constitute thestopper section 32, are energized respectively on the basis of thedetection signal outputted from the first sensor 117 to move the stopperblock 118 downwardly. Therefore, the first end 118 a of the stopperblock 118 abuts against the projection 30 of the fixing band 28 a, 28 bloosely fitted to the boot 18 made of resin. The projection 30 isdetected by the second sensor 121 which is contained in the first end118 a of the stopper block 118. Thus, the projections 30 of the fixingbands 28 a, 28 b are positioned in the substantially horizontal state(see FIG. 20).

That is, starting from the initial position shown in FIG. 17, the firststopper mechanism 82 and the second stopper mechanism 84 are operated asfollows respectively. That is, the stopper block 118 is displaced by thepredetermined distance in the substantially horizontal direction(direction of the arrow D) in accordance with the driving action of thefirst cylinder 90. After that, the stopper block 118 is moved downwardly(in the direction of the arrow F) in accordance with the driving actionof the second cylinder 106 on the basis of the detection signaloutputted from the first sensor 117. Accordingly, the stopper block 118is allowed to abut against the projection 30 which is rotated togetherwith the boot 18 made of resin (see FIG. 18). The stopper block 118abuts against the projection 30 of each of the fixing bands 28 a, 28 b.Accordingly, each of the projections 30 is positioned at the positiondisposed in the substantially horizontal direction (lateral direction)of the boot 18 made of resin.

In this case, even in the state in which the projection 30 is positionedat the predetermined position by the stopper block 118, the boot 18 madeof resin and the drive shaft 16 are in the rotating state in accordancewith the driving action of the rotary driving source 24, due to theclearance between the boot 18 made of resin and the fixing band 28 a, 28b. As described above, it is possible to avoid the co-rotating state andthe wavy state of the fixing bands 28 a, 28 b by the aid of the tubes119 a, 119 b and the pressing tab 123 provided for the first and secondstopper mechanisms 82, 84.

The fact that the projection 30 is positioned at the predeterminedposition is confirmed by the detection signal from the second sensor121. When the stopper block 118 does not abut against the projection 30of the fixing band 28 a, 28 b, namely when the projection 30 is notpositioned at the predetermined position, then the stopper block 118 ismoved upwardly in accordance with the driving action of the secondcylinder 106 to give the waiting state at the initial position.

In the embodiment of the present invention, the second sensor 121 iscontained in the first end 118 a of the stopper block 118 which makesabutment against the projection 30 of the fixing band 28 a, 28 b. Thesecond sensor 121 is arranged at the portion which is deviated by thepredetermined distance in the substantially horizontal direction via therecess from the substantially central portion of the first end 118 a ofthe stopper block 118 (see FIG. 22). Further, as shown in FIG. 28, thefirst sensor 117 and the second sensor 121 are designed to sense a pinpoint H and a pin point I on the wall surface 205 protruding from theflat surface section 203 of each of the fixing bands 28 a, 28 b andbeing continuous to the projection 30. The pin point H is a detectionpoint to detect the timing when the stopper block 118 is moveddownwardly. The pin point I is a detection point to detect theprojection 30 which abuts against the stopper block 118. The pin pointsH and I are arranged substantially in parallel at portions deviated bypredetermined distances in the substantially horizontal direction fromthe central portion of each of the fixing bands 28 a, 28 b.

Therefore, the first sensor 117 and the second sensor 121 do not detectthe stepped section 204 (see FIG. 21) formed by the first end on theouter circumferential side of the fixing band 28 a, 28 b wound in thesubstantially circular configuration. Further, the first sensor 117 andthe second sensor 121 do not detect the hook-shaped fastening pawls 200a to 200 c to be fastened to the fastening holes 202 a to 202 c of thefixing bands 28 a, 28 b.

In other words, when the detection points to be sensed by the firstsensor 117 and the second sensor 121 are set to be the pin point H andthe pin point I which are deviated by the predetermined distances in thesubstantially horizontal direction from the central portion of thefixing band 28 a, 28 b, then the first sensor 117 and the second sensor121 can detect only the projection 30 of the fixing band 28 a, 28 b in areliable manner, without detecting the hook-shaped fastening pawls 200 ato 200 c and the stepped section 204 formed at the first end on theouter circumferential side of the fixing band 28 a, 28 b. Therefore, itis possible to avoid such erroneous detection that the stepped section204 and the hook-shaped fastening pawls 200 a to 200 c are detected asthe projection 30, and it is possible to improve the detection accuracy.

Subsequently, in the state in which the projections 30 of the fixingbands 28 a, 28 b are positioned, the first tightening mechanism 124 andthe second tightening mechanism 126 for constructing the band-tighteningsection 34 are operated respectively to tighten the fixing bands 28 a,28 b in accordance with the forcible nipping action effected by the pairof pawls 172 a, 172 b in the state in which the projection 30 is held bythe holding section 186.

That is, the third cylinder 132 is driven, and the eighth plate 138 isdisplaced in the direction of the arrow D in accordance with the guidingaction of the linear guide 136. Accordingly, the joint means 152 and theforcible nipping means 153 are displaced in an integrated mannertogether with the eighth plate 138. The holding section 186, which isprovided between the pair of pawls 172 a, 172 b, abuts against theprojection 30 of the fixing band 28 a, 28 b (see FIG. 23). After theprojection 30 of the fixing band 28 a, 28 b is held in the substantiallyhorizontal state by the holding section 186, the rotary driving source24 is deenergized to stop the rotation of the boot 18 made of resin andthe drive shaft 16.

In the state in which the projection 30 of the fixing band 28 a, 28 b isheld substantially horizontally by the holding section 186, each of thestopper blocks 118 is moved upwardly in accordance with the drivingaction of the second cylinder 106. Accordingly, the stopper block 118 isseparated from the projection 30. Further, when the shaft 150 isdisplaced in the direction of the arrow D in accordance with the drivingaction of the fourth cylinder 146, the pair of pawls 172 a, 172 b areoperated in the directions to make approach to one another with thesupport points of the pins 176 to forcibly nit the projection 30 (seeFIG. 26).

That is, when the fourth cylinder 146 is driven, the shaft 150, which isconnected to the piston rod 148 coaxially via the joint means 152, isdisplaced in an integrated manner in the direction of the arrow D. Theengaging section 166, which is formed at the first end of the shaft 150,is wedged into the space between the pair of rollers 178 by the aid ofthe inclined surfaces 164 a, 164 b. Accordingly, the pair of rollers 178are separated from each other, and the pawls 172 a, 172 b approach toone another with the support points of the pins 176. As a result, theprojection 30 of the fixing band 28 a, 28 b is forcibly nipped by thepawls 172 a, 172 b of the pair of forcible nipping segments 174 a, 174b. Accordingly, the fixing bands 28 a, 28 b are tightened substantiallysimultaneously (see FIGS. 24 and 25).

After the tightening operation for the fixing band 28 a, 28 b iscompleted, the fourth cylinder 146 is driven to displace the shaft 150in the direction (direction of the arrow C) opposite to the above.Accordingly, the projection 30 is released from the forcible nippingstate. That is, the engaging section 166 of the shaft 150 is separatedfrom the space between the pair of rollers 178. The pair of rollers 178approach to one another in accordance with the resilient force of thespring member 196 fastened to the pins 194. Accordingly, the pair ofpawls 172 a, 172 b are operated in the directions to make separationfrom each other with the pins 176 as the support points. Thus, theprojection 30 is released from the forcible nipping state.

Further, the eighth plate 138 is displaced in the direction (directionof the arrow D) opposite to the above in accordance with the drivingaction of the third cylinder 132, and the first cylinder 90 and thesecond cylinder 106 are driven. Thus, the first stopper mechanism 82 andthe second stopper mechanism 84 are restored to the initial positions.

In the embodiment of the present invention, owing to the provision ofthe bellows section-pressing mechanism 37, even when the bellows section35 of the boot 18 made of resin is deformed, the fixing band 28 b can besmoothly installed to the small diameter annular attachment sectiondisposed closely to the bellows section 35, without making the contactof the pawls 172 a, 172 b with the deformed portion. Therefore, thebellows section 35 of the boot 18 made of resin is not damaged, and theforward/backward movement of the pawls 172 a, 172 b for forcibly nippingthe projection 30 of the fixing band 28 b is not obstructed. As aresult, the occurrence of the trouble is previously avoided, which wouldbe otherwise caused, for example, such that the operation of the fixingband-tightening apparatus 10 is stopped. Therefore, the tighteningoperation for the fixing band 28 b is smoothly performed, and it ispossible to improve the production efficiency.

In the embodiment of the present invention, the following effect isobtained. That is, owing to the provision of the large diameter side andsmall diameter side end-positioning mechanisms 39 a, 39 b respectively,even when the large diameter and/or small diameter annular attachmentsection of the boot 18 made of resin is deviated from the predeterminedposition, the positional discrepancy can be corrected to effect thepositioning at the predetermined position. Further, the fixing band 28a, 28 b is installed to the large diameter and/or small diameter annularattachment section while maintaining the positioned state. Therefore,the large diameter and/or small diameter annular attachment section isreliably constricted at the predetermined position of the cup section 83and/or the drive shaft 16 by means of the fixing band 28 a, 28 b.

In the embodiment of the present invention, the projection 30 of thefixing band 28 a, 28 b is forcibly nipped in the state of beingpositioned in the substantially horizontal direction by means of thefirst stopper mechanism 82 and the second stopper mechanism 84.Therefore, substantially the same positional relationship is obtainedwith respect to the position for performing the welding and fusing byradiating the laser beam onto the steel belt 198 a, 198 b to beinstalled to the boot 20 made of rubber of the tripod type constantvelocity universal joint 14. As a result, the layout can be harmonizedwith the existing apparatus (not shown), and it is possible to improvethe versatility. It is unnecessary to change the existing productionline. Therefore, it is possible to reduce the production cost in view ofthe fact that no new equipment investment is required.

In the embodiment of the present invention, the fixing bands 28 a, 28 bcan be installed substantially simultaneously to the large diameterannular attachment section and the small diameter annular attachmentsection of the boot 18 made of resin respectively by using the firsttightening mechanism 124 and the second tightening mechanism 126 whichare constructed in substantially the same manner. Therefore, it ispossible to improve the production efficiency.

The following problem may arise. That is, when the boot 18 made of resinand the fixing band 28 a, 28 b are rotated in an integrated manner inaccordance with the driving action of the rotary driving source 24, thenthe fixing band 28 a to be installed to the large diameter annularattachment section of the boot 18 made of resin is in the wavy state,while the fixing band 28 b to be installed to the small diameter annularattachment section makes co-rotation.

However, in the embodiment of the present invention, the second stoppermechanism 84 on the side of the large diameter annular attachmentsection is provided with the pressing tab 123 for making contact underpressure with the projection 30 by the aid of the resilient force of thespring member 122. Accordingly, it is possible to avoid the occurrenceof the wavy state and the co-rotation. Further, in the embodiment of thepresent invention, the first stopper mechanism 82 on the side of thesmall diameter annular attachment section is provided with one or aplurality of tubes 119 a, 119 b connected to the unillustrated airsupply source. The air is discharged toward the rotating fixing band 28a, 28 b from the blow ports 120 of the tubes 119 a, 119 b. Accordingly,it is possible to avoid the occurrence of the wavy state and theco-rotation.

The tubes 119 a, 119 b for discharging the air may be provided for thesecond stopper mechanism 84 on the side of the large diameter annularattachment section, and the pressing tab 123 for making contact underpressure with the projection 30 in accordance with the action of thetensile force of the spring member 122 may be provided for the firststopper mechanism 82 on the side of the small diameter annularattachment section. Alternatively, the pressing tab 123 and the tubes119 a, 119 b may be simultaneously provided.

In the embodiment of the present invention, the detection points to besensed by the first sensor 117 and the second sensor 121 are set to bethe pin point H and the pin point I deviated by the predetermineddistances in the substantially horizontal direction from the centralportion of the fixing band 28 a, 28 b. Accordingly, the hook-shapedfastening pawls 200 a to 200 c and the stepped section 204 formed at thefirst end on the outer circumferential side of the fixing band 28 a, 28b are not detected by the first sensor 117 and the second sensor 121.Only the projection 30 of the fixing band 28 a, 28 b is reliablydetected. Therefore, the erroneous detection, in which the steppedsection 204 and the hook-shaped fastening pawls 200 a to 200 c aredetected as the projection 30, is avoided, and it is possible to improvethe detection accuracy by detecting the projection 30 of the fixing band28 a, 28 b as the pin point by using the second sensor 121.

Next, detailed explanation will be made below for a fixingband-tightening method for the boot 18 made of resin for the constantvelocity universal joint.

As shown in FIG. 29, the constant velocity universal joint 310 comprisesa cylindrical outer cup 316 having an opening 314 integrally connectedto a first end of an unillustrated drive shaft. An inner member (notshown), which includes, for example, spiders and rollers connected to afirst end of a driven shaft 318, is accommodated in the outer cup 316.

The constant velocity universal joint 310 is further provided with theboot 18 made of resin for surrounding a predetermined range of the outercup 316 and the driven shaft 318. The boot 18 made of resin has abellows section 320 which is formed to have a bellows-shapedconfiguration, a large diameter annular attachment section 322 which isformed integrally at both ends of the bellows section 320 and which hasa large diameter to be installed to the outer circumferential surface ofthe outer cup 316, and a small diameter annular attachment section 324which has a small diameter to be installed to the outer circumferentialsurface of the driven shaft 318.

The large diameter annular attachment section 322 and the small diameterannular attachment section 324 are formed to have substantially the sameconfiguration except that they merely differ in diameter. Therefore, thesame constitutive components are designated by the same referencenumerals.

As shown in FIG. 30, the large diameter annular attachment section 322is formed with a band-mounting groove 328 which is composed of a recesswith a width slightly wider than the width of the fixing band 28 a andwhich extends in the circumferential direction, and an annular groove330 which circumscribes at a substantially central portion of theband-mounting groove 328 respectively.

As shown in FIG. 30, the band-mounting groove 328 is formed with a firstsmall projection 332 a and a second small projection 332 b (frictionalcoefficient-increasing mechanism) which are separated from each other bya predetermined spacing distance with the annular groove 330 interveningtherebetween respectively. Each of the first small projection 332 a andthe second small projection 332 b is formed with a verticalcross-sectional configuration which is a curved circular arc-shapedconfiguration as viewed from the side of the driven shaft (see FIG. 32).On the other hand, each of them is formed with a verticalcross-sectional configuration which is a substantially rectangularconfiguration as viewed in a direction substantially perpendicular tothe axis of the driven shaft (see FIG. 31).

Alternatively, as shown in FIG. 33, it is also preferable to providefirst and second small projections 333 a, 333 b, each of which is formedto have a substantially acute-angled apex protruding upwardly in avertical cross-sectional configuration as viewed in the directionsubstantially perpendicular to the axis of the driven shaft 318.

As shown in FIG. 34, three pairs of first small projections 332 a andsecond small projections 332 b as described above are arranged andseparated from each other by spacing distances of about 120 degrees inthe circumferential direction. However, there is no limitation thereto.It is also preferable that a single set or a plurality of sets of smallprojections separated from each other by a predetermined angle in thecircumferential direction are formed, or they may be constructed to becontinuous in the circumferential direction.

As shown in FIGS. 35 to 37, the first small projection 332 a and thesecond small projection 332 b, which are formed at the band-mountinggroove 328 of the small diameter annular attachment section 324, areformed in the same manner as those of the large diameter annularattachment section 322.

In this arrangement, the first small projection 332 a and the secondsmall projection 332 b, which are separated from each other by thepredetermined spacing distance with the annular groove 330 interveningtherebetween, are formed respectively. Accordingly, the fixing band 28a, 28 b can be stably fixed in the band-mounting groove 328.

A curves surface section 338, which is gently curved, is formed on eachof lower surfaces of the large diameter annular attachment section 322and the small diameter annular attachment section 324. It is designedthat when the fixing band 28 a, 28 b is constricted, the curved surfacesection 338 is pressed to exhibit the sealing function.

Next, modified embodiments of the small projection to function as thefrictional coefficient-increasing mechanism are shown in FIGS. 38 to 42.

In a first modified embodiment, a plurality of small projections 340,which are separated from each other by predetermined spacing distancesin the circumferential direction, are formed on an inner wall on theside of the bellows section 320 of the band-mounting groove 328 (seeFIG. 38). The small projection 340 is formed to have a substantiallytriangular configuration as viewed from an upper position (see FIG. 39).The small projection 340 is formed with an inclined surface 342 slantingdownward to the left from the side of the bellows section 320 toward thefixing band 28 a (28 b) in a vertical cross-sectional configuration asviewed in the direction substantially perpendicular to thecircumferential direction (see FIG. 40).

The small projection 340 has a tapered section 344 which is formed to begradually tapered toward the opposing other wall surface of theband-mounting groove 328. The tapered section 344 is provided to makeengagement with a side surface 346 of the fixing band 28 a (28 b) in thecircumferential direction (see FIG. 40).

Alternatively, the plurality of small projections 340, which areseparated from each other by the predetermined spacing distances in thecircumferential direction, may be formed on the wall surface on the sideopposite to the bellows section 320 (see FIG. 41). Furtheralternatively, the small projection may be formed to be continuous inthe circumferential direction on the wall surface on the side of thebellows section 320 of the band-mounting groove 328 or on the wallsurface on the side opposite to the side of the bellows section 320.

In a second modified embodiment, as shown in FIG. 42, a first smallprojection 348 a and a second small projection 348 b, which slightlyprotrude upwardly, are formed on the upper side of an annular groove 330respectively. Accordingly, the contact surface with respect to the lowersurface portion of the fixing band 28 a (28 b) is decreased to increasethe contact surface pressure. Thus, an advantage is obtained such thatthis arrangement causes less sliding.

The first small projection 348 a and the second small projection 348 bshown in FIG. 42 may be formed as a plurality of individuals which areintermittently separated from each other by predetermined spacingdistances in the circumferential direction respectively, or they may beformed to have a continuous circumscribing configuration in thecircumferential direction.

Next, explanation will be specifically made below for the fixingband-tightening method for the boot 18 made of resin for the constantvelocity universal joint.

At first, the rotary driving source 24 is driven so that the firstconstant velocity universal joint 12, the second constant velocityuniversal joint 14, and the drive shaft 16, which are coaxially held bythe first holding mechanism 38 and the second holding mechanism 42, arerotated in an integrated manner respectively. In this process, thefixing band 28 a, 28 b is loosely fitted to the large diameter annularattachment section 322 of the boot 18 made of resin with a slightclearance. When the boot 18 made of resin is rotated, the fixing band 28a, 28 b is also rotated in accordance therewith. Therefore, theprojection 30 of the fixing band 28 a, 28 b is rotated in apredetermined direction about the center of the central axis of thedrive shaft 16.

That is, the plurality of first small projections 332 a and theplurality of second small projections 332 b (or the small projections340 or the first small projections 348 a and the second smallprojections 348 b), which are formed and separated from each other bythe predetermined spacing distances on the wall surface in thecircumferential direction of the band-mounting groove 328, are engagedwith the side surface of the fixing band 28 a, 28 b in thecircumferential direction respectively. Thus, the frictional coefficientis increased.

Therefore, when the fixing band 28 a, 28 b formed of the metal materialis loosely fitted to the boot 18 made of resin with the slightclearance, the frictional coefficient, which is generated between thelarge diameter annular attachment section 322 and the fixing band 28 a,28 b, is increased, for example, by the aid of the plurality of firstsmall projections 332 a and the plurality of second small projections332 b formed for the band-mounting groove 328. Accordingly, it ispossible to integrally rotate the loosely fitted fixing band 28 a, 28 band the boot 18 made of resin in a reliable manner.

Subsequently, the projection 30 of the fixing band 28 a, 28 b, which isin the rotating state before arrival at the substantially horizontalstate, is detected by the first sensor 117 and the second sensor 121(see FIG. 19). When the first stopper mechanism 82 and the secondstopper mechanism 84, which constitute the stopper section 32, areenergized, the projection 30 of the fixing band 28 a, 28 b is positionedin the substantially horizontal state (see FIG. 20)

In this process, even in the state in which the projection 30 ispositioned at the predetermined position by the aid of the stopper block118, the boot 18 made of resin and the drive shaft 16 are in therotating state in accordance with the driving action of the rotarydriving source 24, owing to the clearance between the boot 18 made ofresin and the fixing band 28 a, 28 b.

In the state in which the projection 30 of the fixing band 28 a, 28 b ispositioned in the substantially horizontal direction, the firsttightening mechanism 124, which constitutes the band-tightening section34, is displaced to hold the projection 30 by the aid of the holdingsection 186. After that, the stopper block 118 is moved upwardly toseparate it from the projection 30. Further, the rotary driving source24 is deenergized to stop the rotation of the boot 18 made of resin andthe drive shaft 16.

Further, the first tightening mechanism 124 is energized, and the fixingband 28 a, 28 b is tightened in accordance with the forcible nippingaction by the pair of pawls 172 a, 172 b in the state in which theprojection 30 is held by the holding section 186. Thus, the tighteningoperation for the fixing band 28 a, 28 b is completed.

In the fixing band-tightening method for the boot 18 made of resin forthe constant velocity universal joint, when the projection 30 of thefixing band 28 a, 28 b is forcibly nipped in the state in which the boot18 made of resin and the fixing band 28 a, 28 b are integrally rotatedin accordance with the driving action of the rotary driving source 24,the frictional coefficient, which is generated between the boot 18 madeof resin and the fixing band 28 a, 28 b formed of the metal material,can be increased by providing the first small projections 332 a and thesecond small projections 332 b for making engagement with the outersurface of the fixing band 28 a, 28 b on the wall surface of theband-mounting groove 328.

In other words, the friction is actively generated between the fixingband 28 a, 28 b and the band-mounting groove 328 to which the fixingband 28 a, 28 b is installed. Accordingly, when the tightening operationfor the fixing band 28 a, 28 b is performed, the boot 18 made of resinand the fixing band 28 a, 28 b are rotated and moved reliablyrespectively.

Therefore, the boot 18 made of resin and the fixing band 28 a, 28 b canbe reliably engaged with each other. Further, the projection 30, whichis positioned in the substantially horizontal direction in the state inwhich the both are rotated in the integrated manner, can be forciblynipped to constrict the fixing band 28 a, 28 b.

As a result, the operation for tightening the fixing band 28 a, 28 b bythe fixing band-tightening apparatus 10 can be automated smoothly andefficiently. The constricting position, at which the fixing band 28 a,28 b is tightened, can be stabilized at the predetermined position. Anadvantage is obtained such that the commercial property concerning theappearance is improved.

For example, even when a minute amount of lubricating oil adheres to thelarge diameter annular attachment section 322 and/or the small diameterannular attachment section 324 of the boot 18 made of resin or to thefixing band 28 a, 28 b, the frictional coefficient, which is generatedbetween the fixing band 28 a, 28 b and the boot 18 made of resin, isincreased to be less slippery. Thus, it is possible to avoid the looserotation of the fixing band 28 a, 28 b with respect to the boot 18 madeof resin.

Further, owing to the function of the self-weight of the projection 30of the fixing band 28 a, 28 b made of metal, it is possible to avoid theloose rotation of the fixing band 28 a, 28 b.

What is claimed is:
 1. A fixing band-tightening method for forciblynipping and deforming a projection of an annular fixing band looselyfitted to a workpiece having a shaft-shaped configuration so that adiameter of said fixing band is reduced to fix said fixing band to saidworkpiece, said fixing band-tightening method comprising the steps of:integrally rotating, in a circumferential direction of said workpiece,said fixing band loosely fitted to a shaft section of said workpiecewith a clearance intervening therebetween, in accordance with a drivingaction of a rotary driving source; temporarily positioning a projectionin a lateral direction except for a vertical direction by allowing astopper block to abut against said projection of said rotating fixingband; positioning said projection at a predetermined position bypressing said temporarily positioned projection by means of a holidaysection, and deenergizing said rotary driving source to stop saidrotation; and forcibly nipping said projection held at saidpredetermined position by said holding section so that said fixing bandis tightened and fixed to said workpiece.
 2. A fixing band-tighteningmethod for a boot for a constant velocity universal joint for tighteningand constricting a fixing band with respect to said boot to be installedto said constant velocity universal joint, said method comprising thesteps of: rotatably holding said constant velocity universal jointinstalled with said boot made of resin with its axis as a center ofrotation with respect to a fixing band-tightening apparatus; looselyfitting said fixing band to a band-mounting groove of at least any oneof a large diameter annular attachment section and a small diameterannular attachment section of said boot made of resin to temporarilyassemble said fixing band; integrally rotating said boot made of resinand said fixing band in a state in which a frictional coefficientbetween said loosely fitted fixing band and said boot made of resin isincreased by means of a frictional coefficient-increasing mechanismformed for said band-mounting groove, in accordance with a drivingaction of a rotary driving source provided for said fixingband-tightening apparatus; and tightening and constricting said fixingband by positioning, at a predetermined position, a projection of saidfixing band rotating together with said boot made of resin, and forciblynipping said projection in said positioned state.
 3. The fixingband-tightening method for said boot for said constant velocityuniversal joint according to claim 2, wherein said projection of saidfixing band to forcibly nipped in a state of being positioned at aposition in a substantially horizontal direction.
 4. The fixingband-tightening method for said boot for said constant velocityuniversal joint according to claim 2, wherein said frictionalcoefficient-increasing mechanism comprises a first small projection anda second small projection which are separated from each other with anannular groove formed at a substantially central portion of saidband-mounting groove intervening therebetween.
 5. The fixingband-tightening method for said boot for said constant velocityuniversal joint according to claim 4, wherein said first and secondsmall projections are composed of a plurality of individuals which areseparated from each other by predetermined spacing distances in acircumferential direction.
 6. The fixing band-tightening method for saidboot for said constant velocity universal joint according to claim 4,wherein said first and second small projections are formed continuouslyin said circumferential direction.
 7. The fixing band-tightening methodfor said boot for said constant velocity universal joint according toclaim 2, wherein said frictional coefficient-increasing mechanismcomprises a first small projection and a second small projection whichprotrude upwardly from an annular groove formed at a substantiallycentral portion of said band-mounting groove.
 8. The fixingband-tightening method for said boot for said constant velocityuniversal joint according to claim 2, wherein said frictionalcoefficient-increasing mechanism comprises a small projection formed ona wall surface on a side of a bellows section of said band-mountinggroove.
 9. The fixing band-tightening method for said boot for saidconstant velocity universal joint according to claim 8, wherein saidsmall projection has a substantially triangular configuration as viewedfrom a upper position, and it is formed to have a tapered configurationin which a vertical sectional configuration substantially perpendicularto a circumferential direction has an inclined surface inclined towardsaid fixing band.
 10. The fixing band-tightening method for said bootfor said constant velocity universal joint according to claim
 2. whereinsaid frictional coefficient-increasing mechanism comprises a smallprojection formed on a wall surface on a side opposite to a wall surfaceon a side of a bellows section of said band-mounting groove.